将 NSDiffableDataSourceSnapshot 应用于 UICollectionViewDiffableDataSource 导致 'NSInternalInconsistencyException'

Question

我正在尝试为我的 collectionView 实施 UICollectionViewDiffableDataSource。我的代码编译正常，但是我在第一次对其应用快照时将运行保留在该错误中，并出现以下错误：

Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'Invalid parameter not satisfying: self.supplementaryViewProvider || (self.supplementaryReuseIdentifierProvider && self.supplementaryViewConfigurationHandler)'

这是我的代码：

    var groups: [Group] = [Group]()
    var dataSource: UICollectionViewDiffableDataSource<Section, Group>!

    // MARK: - View Life Cycle
    override func viewDidLoad() {
        super.viewDidLoad()

        self.searchBar.delegate = self
        self.groups = DummyData.groups

        setupDataSource()
    }

    override func viewDidLayoutSubviews() {
        super.viewDidLayoutSubviews()
        performSearch(searchQuery: nil)
    }


    // MARK: - Helper Functions
    func performSearch(searchQuery: String?) {
        let filteredGroups: [Group]
        if let searchQuery = searchQuery, !searchQuery.isEmpty {
            filteredGroups = groups.filter { [=11=].contains(query: searchQuery) }
        } else {
            filteredGroups = groups
        }

        var snapshot = NSDiffableDataSourceSnapshot<Section, Group>()
        snapshot.appendSections([.main])
        snapshot.appendItems(filteredGroups, toSection: .main)
        dataSource.apply(snapshot, animatingDifferences: true, completion: nil)
    }

    func setupDataSource() {
        dataSource = UICollectionViewDiffableDataSource <Section, Group>(collectionView: collectionView) { (collectionView: UICollectionView, indexPath: IndexPath, group: Group) -> UICollectionViewCell? in

            guard let cell = self.collectionView.dequeueReusableCell(
                withReuseIdentifier: String(describing: MyGroupsCollectionViewCell.self), for: indexPath) as? MyGroupsCollectionViewCell else {
                    fatalError("Cannot create new cell") }

            cell.configure(withGroup: group)

            return cell
        }
    }

如果需要，我可以 post 完整的调用堆栈。

Answer 1

找到答案了。我正在使用故事板创建我的 collectionView 并且不小心将第 Header 部分的属性设置为 true。因此，collectionView 需要将 header 部分的视图拉到某个地方，但我从未告诉它在哪里，因此

parameter not satisfying: self.supplementaryViewProvider || (self.supplementaryReuseIdentifierProvider && self.supplementaryViewConfigurationHandler)

这是我在上面找到的一篇很好的文章，供以后遇到此问题的任何人参考： https://medium.com/@jamesrochabrun/uicollectionviewdiffabledatasource-and-decodable-step-by-step-6b727dd2485

将 NSDiffableDataSourceSnapshot 应用于 UICollectionViewDiffableDataSource 导致 'NSInternalInconsistencyException'

Applying NSDiffableDataSourceSnapshot to UICollectionViewDiffableDataSource causes 'NSInternalInconsistencyException'

uicollectionview

uikit

swift5

diffabledatasource

nsdiffabledatasourcesnapshot